Power-generating stations normally contain large pieces of equipment. The equipment is used constantly when the station is in operation. When the station is shut down for repairs, not only are repairs made; but preventive maintenance is also performed on much of the equipment. Some of the equipment is supported on spherical bearings. Those spherical bearings are mounted in spherical bearing seats which, in some instances, must be refinished during repair or maintenance of the equipment, that is, the bearing seat must be recut into a true sphere. In view of the fact that much of the equipment is substantial in size, it is desirable that the equipment be left in place and machine tools be brought to the equipment to do the work. Certain advantages flow from bringing the machine tools to the equipment rather than moving the equipment to a machine shop. It is not necessary to disassemble other connected equipment in order to do the required machining; and, in the case of large pieces of equipment, it is impractical to move the equipment.
Heretofore, there has been no suitable equipment available for machining spherical bearing seats in place.